Solar Power Generation

DC doesn't have phases unless you count on and off.

The inverter will produce single or three phase depending on what you buy.

I only like 3 PH DC

3PH is too acid. You better use PH=7, wich is ....neutral

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PH > 7 basic

PH = 7 no acidic, no basic

PH < 7 acidic

Fredsky made a joke, a 3phase DC. In the idea of a quasy absurd jokes, I mentioned the PH = 7

Given modern electronic frequency and voltage control can somebody tell me why we still use AC Transmission?

Isn't the RMS power of AC only about 70 percent of DC?

It's easier to step up and down with AC at V high voltages or currents. Ok semi conductors are good... but not that good... yet.
Probably loads of age old reasons which are about transmission lines, magnetisation etc.

I expect the Starship Enterprise is DC

Del

It's because AC doesn't have the distance limits DC has on transmission lines. That was the killer for Edison and why Tesla and Westinghouse won out on power transmission/generation systems.

That's a myth. DC has no skin effect so all of the cross sectional area of a conductor conducts. Transmission line equations are much simpler when ω=0. The technology to change voltages is easier with AC than DC, particularly when the grids were first deployed. This makes it easier to compensate for transmission line losses and not to minimize the losses.

This is true, but as the power increases, so to must the current or the voltage. And so, in DC you can't easily step up the voltage so you must increase the size of the conductor. Whereas in AC you can easily step up and then step down the voltage and get more power over the same size conductor. In long distance high power transmission, that means a huge difference in cost of wire and infrastructure to support it.

https://en.wikipedia.org/wiki/War_of_Currents

Steinmetz would disagree with you on the skin effect. He wrote the book, literally and figuratively on the subject. Page 14 Electric Discharges, Waves and Impulses; Charles Proteus Steinmetz.

More can be found on the subject in his other writings. But the current is always on the surface of a conductor, no matter how small or large. But the effect is most pronounced in high-frequency AC, so is largely ignored at low frequencies and in DC curcuits...until there is a transient! Like opening or closing a switch or the creation of a short.

Great information - Thanks!!!!!

Due to a design defect (with which I got UL's attention) in a Maytag AC electric resistance dryer coil tube system, the burn-through of the coil and its subsequent explosively shorting to the tube housing, thereby severing the conductive circuit of the heating coil, occurred so fast that the panel breaker did not trip and the cold dryer spun through the rest of its cycle sans heat. Having a dangling 120 volts worth of open circuit microns from re-shorting is a situation that may be happening a lot more frequently than the mavens of the NEC would care to contemplate.

There is a better control with AC transmission Gavilan.

Voltage step up and down is harder, expensive, inefficient and inconvenience in DC transmission compared to AC transformers.

Switches, circuit breakers and disconnects physical gap sizing is the actual reason AC instead of DC is used for power transmission. Interrupting an AC arc path is significantly shorter length than DC because 50 or 60 times a second the current goes to zero.

Actually 100 or 120 times a second... But who's counting

1) Lower component installation and replacement cost.

2) Much easier and simpler to manipulate voltage level control for supplying lower voltage loads by using transformers instead of complicated, costly, high maintenance inverters.

3) Lower overall maintenance cost due to technical simplicity of AC components that require much less PM attention than DC components.

4) Because the cost to convert the existing power distribution grid would be phenomenal with the time required to do so causing extreme unreliability and instability issues that would result in serious profit losses for not only the power generation suppliers but also most manufacturing facilities.

If there's one thing I never want to see again it is a DC ACB open under fault.

Absolutely me too! Further more I hope I never have the duty to clean up the aftermath! (I had to wash my pants and drawers twice to get them clean.)

Meanwhile back at the question.

If you want to grid tie to three phase, you could have 3 sepatate sets of panels and an inverter for each tying in one to each phase.

Del

Inverter.

You have to add RLC circuit [IGBT amplified PWM modulator] with 3 outputs each one emits sinusoidal wave (voltage) with some amplitude to your liking(but limited on PV power capacity, of course) and each one 60⁰ off phase from one another.

Three phase power is a sort of concentrated energy transmission. You must have lots of panels and/or battery banks then, ganesh88.

Not sure ... But I hope there may be a Inverter(Three phase) which can convert DC power to Three phase AC power.

And I will feel better If someone explain about the technology for maintaining the phase angle between the three phases for the output power from Inverter.

Have a look on google for the various manufacturers information.

You will "feel a lot better" If you spend some time studying and understanding the field of Electrical Engineering!

Try a basic internet or Wikipedia search first please. All the basics are laid out there to help further educate you in the fundamental concepts.